Rock-drill



(No Model.)

T. SYMONDS.

ROCK DRILL.

No. 542,542. Patented July 9, 1895.

1 m 1 34 .w wr 7 J. W M Z k a H\\\\\\\\\\\\\\\\\\\\ k 2 F NITED i STATES THOMAS SYMONDS, OF LEOMINSTER, MASSACHUSETTS.

ROCK-DRILL.

SPECIFICATION forming part of Letters Patent No. 542,542, dated July 9, 1895.

Application filed February 15, 1893. Renewed June '7, 1895- Serial No. 552,035. (No model.)

To all whom it may concern.-

Be it known that I, THOMAS SYMONDS, a citizen of the UnitedStates, and a resident of Leominster, Massachusetts, have invented certain Improvements in Rock Drills, of which the following is a specification.

My invention relates to certain improvements in rock-drills and has for its object the construction of a drill having its cutting edges so arranged as to act more effectively than those commonly in use and which will act to readily clear itself of the disintegrated rock or other substance being drilled and provide for a circulation of water from the base of the cutting-edge to a point above the mouth of the opening being drilled, so that the mixture of disintegrated rock and water will be carried up and discharged above the opening and will not tend to fill the hole when the drill is Withdrawn. p

In the accompanying drawings, Figure 1 is a sectional view of a drill and its carryingshank constructed in accordance with my invention. Fig. 2 is a perspective View illustrating the disposition of the cutting-edges. Fig. 3 is a plan view showing the cuttingedges;' and Fig. 4 is a sectional perspective view on the line 4 4, Fig. 3. r

The cutting-face of the drill Ais provided with a series of cutting-edges a, b, b, c, 0', c and 0 The cuttingedge a extends completely across the face of the tool in a diametral line. The cutting-edges Z) I) extend at a rightangle to the cutting-edge a and are also arranged on a diametral line and provided with inclined ends '01, which extend down to the point where the base of the cutting-edge a, merges into the body of the tool. arranged on the periphery of the tool in the spaces formed between the diametra1ly-arranged cutting-edges a b b,'and at the opposite ends of the peripheral cutting-edges are inclined faces 6, extending down to the base of the cutting-edges a b Z), and from the periphery the inner faces of the cutting-edges slope toward the center of the base, so as to force the disintegrated rock in toward the center of the tool.

In the spaces formed between the diametrally-arranged cutting-edges are a series of openings g, extending up forsome distance The cutting-edges c, c, 0 and 0 are in the base and communicating with a discharge-pipe G in the drill and shank. The arrangement of the mouths of the openings g, with respect to the inclined faces of the various cutting-edges being such that all of the material through which the tool is forced. will be directed toward the mouths of these openings and forced by the rapid vibration of the drill to enter the openings with the accumulated water, and find its way to the hollow shank B. I

Tools of this class are reciprocated at a high rate of speed, and at each reciprocation the tool is given a radial movement, generally to an extent equal to about one-eighth of its circumference, so that each time the tool reciprocates the cuttingedges will come into contact with a fresh portion of the rock, the peripheral cutting-edges acting to keep the hole drilled perfectly and at the same time make a clean straight opening.

Drills of this class as ordinarily constructed and the drills in common use, are provided with cutting'edges arranged on diametral lines at right angles to each other, and it. has been found in practice that the outer ends of the cutting-edges have much greater wear than the inner ends of the same owing to the fact that the outer edges are at all times in frictional contact, to a greater or less extent, with the surfaces ot'the opening being drilled and at the same time these outer ends have much more ground to cover and much more work to do than that portion of the cuttingedgcs situated at the center of the tool, and it is to avoid this uneven wear that the peripheral cutting-edges are provided.

The shank B is made of sutticientlength to extend above the mouth of the opening being drilled and at-its upper end is connected to the usual drill-rod extending to the clutch of the reciprocated plunger of the rock-drill cylinder and near its upper end is provided with a chamber H, having outlet-openings on its periphery at h of sufficient diameter to permit the free discharge of the disintegrated rock and water which rises through the passage G.

At the lower portion of the chamber H is formed a valve-seat 2', on which is seated an ordinary puppet-valve I secured to a guidingstcm is adapted to a suitably-shaped recessl in the end of the drill-rod, and surrounding this stem is a light spring m, which normally will keep the valve closed; but when the drill is on the downward stroke the pressure in the passage G will raise the valve and permit the discharge of a portion of the material contained in the passage through the opening h, while on the upstrokethe valve will be closed tightly to its seatand will prevent any back circulation and the forcing of the disintegrated rock back to the cutting-edges.

With a construction of drill such as that described I am enabled to drill an opening much quicker than can be accomplished with drills as now constructed and at the same time the peripheral cutting-edges Willprevent to a great extent the Wear of the main cuttingedges a b b, and it will not be necessary to sharpen the drill so frequently, and at the same time the circnlatingpassages in the body of the drill, extending as they do directly to the cutting-edges, will remove all the disintegrated rock and water and prevent an accumulation of material at the bottom of the opening, while the discharge of such material is facilitated by the inclining of all of pressed valve adapted to said valve seat so 10- cated as to permit the free discharge of the disintegrated rock and water rising through said discharge at all' times, substantially as described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

THOMAS SYMONDS. WVitnesses:

FRANK E. BECHTOLD, J OSEPH H. KLEIN. 

